Blowout preventer and tubing head for pumping wells



1951 e. L. CARDWELL 2,563,155

BLOWOUT PREVENTER AND TUBING HEAD FOR PUMPING WELLS Filed Jan. 12, 1946 25 mm m :3 14

I I9 6 a a 5 12 IN V EN TOR.

Glemi L; Carxd'well T To RNEM Patented Aug. 7, 1951 r BLOWOUT PREVENTER A'ND TUBING HEAD FOR PUMPING WELLS Glenn L. Cardwell, Long Beach, Calif assignor to Signal Oil and Gas Company, Los Angeles, Calif., a corporation of Delaware Application January 12, 1946, Serial No. 640,890

e Claims. (01.136515) 7 f This invention relates to, a tubing head for pumping wells, and particularly to blowout preventers for such pumpingwells.

A. conventional manner for pumping oil wells is by means of a reciprocating pump positioned at the bottom of a string of tubing suspended in the well. The piston of the pump is reciprocated by a string of rods-which is positioned in the tubing and projects through the upper end of the tubing. A packing is positioned at the end of the tubing and the rods project through the packing and are connected to and reciprocated by an oscillating beam called the walking beam. The portion of the rod projecting through the packing and reciprocated therein is called the "polish rod. It is connected to the walking beam by a clamp.

Quite frequently, and sufficiently frequent to constitute a hazard to oil well production, the polish rod, due to fatigue failure, breaks oiT at the clamp and the rods and pump fall into the well through the packing. This opens the tubing to atmosphere. In most wells, other than socalled stripper wells, there is enough gas pressure to spew the oil and gas through the open tube and packing. This covers thesurrounding territory with oil and constitutes a fire hazard.

. I have devised a blowout preventer which auto- .matically closes the tubing when such failure of the polish rod occurs.

My invention will be further described in nection with the drawings, in which:

Fig. 1 is an assembly, partly in section, of a tubing head employing my invention;

Fig. 2 is a vertical sectional view of the blowout preventer with the polish rod removed but with the plug in its retracted position as in operation inFig. 1;

Fig. 3 is a view similar to Fig. 2 but with the plug in the shut-off position; and

Fig. 4 is a sectional view taken on the line of Fig. 3.

. The well tubing 2 is mounted on a conventional tubing hanger l and connected to flow valve3. The tubing is connected by means of a collar 4 to the blowout preventer 5.

v The blowout preventer has a central bore 6 large enough in diameter to pass the'polish'rod 25 and a cross bore 1 of greater diameter than said central bore into which is screwed the retainer 8. The cross bore 1 intercepts thecentral bore 6. The inner diameter of the retainer is substantially equal to that of the bore-l: and is greater in length than the diameter of the central bore 6. A second bore l ispositioned in con- 2' the wall of the blowout preventer diametrically opposed and coaxial with the boreL: ,A removable plug. 1 l; toact as a casing headiclosuregis positioned in the. bore [0. Bore i0 terminates in an enlarged cylindrical recess or counterbore 9. The bores 9 and l are coaxial and substan-v tially equal in diameter. The walls of theblQW-r ou-t preventer are chamfered at [2 at a radiusof. curvature substantially equal to the radius of the plug 13 to permit of a sliding. fit of 13 in. the bores -9 and l. The plug I3. is also chamfered at l 5..;to give a polish rod receiving groove in the face of said plug preferably at a radius of curva-: ture equal to the radiu of the polish rod and V is held back by the polish rod which slides in the plug I3. The plug I 3 is bored out at I4. A spring; retaining chamber 8 is screwed into the bore 1. .A spring. l8 fits insidev the retainer 8 and the bore I i and rests in the recess 11. Thelength of the plug is such that when in the shut-ofiposi: tion, shown in Fig. 3, the plug rests in bore 9 and in the bore 1. V

Mountedin chamber I9 is a packing means. One suitable form is shown in Fig. 1. The packing is mounted by means of a ring 20 screwed into IS. The polish rod packing 2| is placed at iii. :The compression. ring 22 carries a bearing sleeve 23' forming a sliding fit with thepolish rod 25. An annular disc 24 is screwed into 20. The polish rod 25 extends above the. assembly andis carried on hanger 21 by means of a clamp 26. Hangers are mounted in the walking beam 28. This mounting is conventional.

. Should the rods break below the hanger 26 and above the top of 24, the rods 25 will drop through the assembly and into the tube 2 so that the top of, the. rods will be below Hi. There being no rod,

Should the break come below the shut-oil plug." the walking beam on its up-stroke will lift the polish rod out of the tubing head assemblyand the plug, acting asa casing head closure member, will shut ofiin the described manner. Inie'ither.

' case the pressure in the tubing will be maintained is unscrewed and the spring is removed. By un-J screwing plug H, the plug l3 may be pushed back into open starting position.

The above blowout preventer is thus composed of a closure member held in open position by the polish rod which passes through a bore in the blowout preventer, and the closure member moves to close" the borewhen thepolish rod is re.- moved from the bore which is then closed by the movable member. The closure member is thus urged to a closed position positively and acts to shut ofi the flow of fluid in. the well when the polish rod is removed from the bore.

Various modifications will suggest themselves to those skilled in the art. a

While I have described a particular embodiment of my invention for the purpose of illustration, it should be understood, that. various modiincations and adaptations thereof may be made within the spirit of the invention as set forth in the appended claims. h

. l'claim:

.nzA, blowout. preventermember for a pumpingwellycomprising. a: central bore through said casing: head adapted to-receive apump polish rod, :munobsruc'ted cross bore of greater diameter than said central bore intercepting said central bore, said cross bore extending on both: sides of said? central bore, a plug, of substantially the diameter of: said cross-bore and of greater' length than the. diameterof said central bore, in said cross bore, said cross bore being closed at both ends thereof, and yieldable means: for normally urging said plug into closed position across said central bore said; plug extending into said cross bore on both sides of said central bore and malting a circumferential seal around said plug: in said cross bore on both sides of said central boretoclose thesame when apump polish rod-isnot positioned in said centralbore, and a separate polish rod packing: means associated with saideentrallbore.

2. A blowout preventer for a pumping well, comprising a central borethrough said blowout preventer adapted to: receive a pumppollslr rod, an unobstructed cross bore of greater diameter than said centralbore; intercepting said central bore said crossbore unobstructedlyextending on' both sides of saidcentral bore, a plug of'sub stantially the diametenof-said cross bore and of greater length t-hani the diameter ofsai'd centrali I bore,v slidably positioned: in said cross bore, said cross-.bore being closed at-both ends thereof; a spring, a spring and plug receiving chamber-connectedito said: cross bore, saidspring being positinned. behind: said. plug to normally urge said plug: into; closed. position. in. said cnoss bore; said plug being; positioned on both; sideszoi said central; bore: and across said; central boreasaid plug; make a. circumferential seal. around said. plus: in said. cross. borev on, both; sides ofsaid centrahborev and. a polish, rod'receiving groove, in. the: face as said plug to close the same when a pump polish; rod is not, positioned in. said. bore, and. a. separate polishrod packin means associated withsaid. centralibore.

3i'Irr combination; a tubing for a pumping well}, rblowoutpreventer mounted on said tubing}, a centralboretlirough said blowout preventer; a polish rod reciprooably mounted in said casing head; aclosure member for'said central -bore-positioned insaid blowout preventer iir slidingcontact; said polish rod, and means for'forcingsaid closure member against said polish rod-when said==polish rod is-mounted insaid casing head. said means being suflicient toforce said closure 4 1 member into closed position across said central bore to shut said central bore off when said polish rod is not in position in said central bore.

4. A blowout preventer assembly for oil well tubing of a pumping well, comprising a tubing for said well including a fluid discharge conduit connected to said: tubing, a casing head for said tubing positioned above said fluiddischarge conduit, a central bore in said casing head, a packing on said blowout preventer, an oil well polish rod reciprocablypositioned in said packing and said central bore, a cross bore in said blowout preventer positioned in said casing head and intersecting said central bore and extending on both sides of said central bore, a closure member positioned in said cross bore and adapted to extend. acrosssaid; central bore and into said cross bore on each side of said central bore when said poli'si'r rod is not in saidcentral bore, said polish rod, upon positioning in said central bore, holding said closure member iri-sai d cross bore mane side otsaid central: bore, and means-positioned -in said casing head to force said closure member said .polislr rod said-means being sufficient'. to. force: said closure member intoclosed positionwhensaidpolisn rod is not in: position insaidcentrallbore.

5. In combination, a tubing: for a pumping well, a. blowout: preventer mounted onsaid tubing, a central: bore. through: saidblowout preventen-a cross-i bore: inx said casin headintersecting said centnah bore: andextendlng on bothsidesofi-saidi central bore,.. a. polish rod reciprocabl-y mounted in. said centrah bore, a plug positioned in. said CIQSSLbQZE and slidably; fitting in said cross bore. and in. sliding: contact: with. said polish rod, a spring in said cross bore operatively engaging said.piug-:to: hololi plug: in slidingcontact-with said rod, saidxplug fitting across said een tralibore and into; said cross: boreon both sides. off saith centrahborelwhensaid polish rod is out of. contact with: sariiiiplug; I 6. In; combination a blowout preventer' for tubing, tor; a. pumping. well, a central: bore in said tubing a cross bore. intersecting sflid central bore and exten'dingzoir both sides-oi said central borer said cross horesbeingof greater: diameter than said centrall borer. said central bore being cbamferedat:saidgintersectioirto adiameter substantially equal to the diameter of said'crossliore:

' a. plug slidablypositioned in said cross boreof diameter substantially equal to the diameter of saidl cross boreandof lengthgreater thanthe diameter of said central bore; whereby saidf'plug' extends on both sides of said central bore into said cross boreon both sides of saidcent'ral bore, and a resilient means operatively engaging said; plug to resiliently position said; plug; in said closed position said plug. making a. circumierlerr tialseal in.said cross; bore. on bothsides oisaid cross bore. .1 J

7... Incombinatioma tubing; for a pumpingwell, a blowout. preventer; mountedin said; tubing-,.sairli blowout. preventer, comprising a. central; bore;.a

' cross bore of greater diameter thansaidcentraii bore and interseotingssaidwentral bore; said: cross bnreextending onzboth sidesofsaid central bore; azpolislrxodsneciprocably mounted insaid central 1 bore;..a plugpositioned in said cross bore; a"

the plug being substantially greater than the diameter of said central bore.

8. In combination, a tubing for a pumping well, a blowout preventer, said blowout preventer comprisin a cross bore of greater diameter than said central bore and intersecting said central bore, said cross bore extending across on both sides of said central bore, a polish rod reciprocably mounted in said blowout preventer polish rod packer and said central bore, a plug positioned in said cross bore, a spring in said cross bore operatively engaging said plug to resiliently hold said plug in sliding engagement with said polish rod, the diameter of said plug being substantially equal to the diameter of said cross bore and the length of the plug being substantially greater than the diameter of said central bore a polish rod receiving groove in the face of said plug, said plug making a circumferential seal in said cross bore on both sides of said central bore.

9. In combination, a tubing for a pumping well, a blowout preventer mounted on said tubing, a bore through said blowout preventer, a polish rod reciprocally mounted in said bore, a closure member for said bore, means continuously urging said closure member towards closed position in said bore and means including said polish rod to hold tion upon removal of said polish rod from said bore.

GLENN L. CARDWELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 18,948 McNeil et a1 Sept. 12, 1933 1,502,106 Lyne July 22, 1924 1,530,006 Melton Mar. 1'7, 1925 1,572,394 Krebs Feb. 9, 1926 1,587,838 Houk June 8, 1926 1,927,246 Schulte Sept. 19, 1933 2,026,036 Head Dec. 31, 1935 r 2,162,990 Abercrombie et a1. June 20, 1939 2,264,600 Webb Dec. 2, 1941 

